1. Field of the Invention
The present invention generally relates to a seatbelt device for securing a passenger to a seat and ensuring the safety of such passenger, and particularly relates to a seatbelt device comprising a retractor for retracting and protracting a webbing with a power source such as a motor.
2. Description of the Related Art
A seatbelt device comprising a retractor for retracting and protracting a webbing has been conventionally known, for example, as described in U.S. Pat. No. 4,511,097. This typical seatbelt device proposes a combination with a motor for protracting and retracting the webbing.
However, if an emergency situation occurs (disconnection within the motor, for example) and a drive current cannot be supplied to the motor of the seatbelt device, no driving force or braking force will be generated, and it is possible that the motor will slip. In such case, after the webbing is fastened, the webbing can be protracted but will not be automatically retracted, and thus, the slack in the webbing is not removed. Driving a vehicle with a slack in the webbing is undesirable as the passenger's security cannot be sufficiently ensured.
The respective controls mentioned above are performed uniformly without consideration to the different uses of the seatbelt by various passengers, and are not necessarily optimum for each passenger. Thus, a typical conventional passenger security/protection device for vehicles could not, in a sufficient manner, provide a comfortable seatbelt-wearing environment or appropriately secure and protect the passenger.
Although a seatbelt is for securing and protecting the passenger upon a vehicle accident, it is also desired that such seatbelt be disengaged immediately after the accident so that the passenger may escape from such vehicle.
Conventionally, when a vehicle accidentally went underwater, the passenger would remove the webbing from the buckle and open the door or window to escape from such vehicle. In this case, the passenger may instantaneously panic, and try to escape without disengaging his/her seatbelt, and the seatbelt device will therefore hinder the passenger's escape. When a vehicle accidentally rolls over, also, the passenger may panic and try to escape without disengaging the seatbelt.
Upon rescuing a passenger from the rolled over vehicle, it is difficult to disengage the buckle of the seatbelt device as it is mounted on the central side of the vehicle interior. Thus, the webbing is often cut in order to rescue the passenger.
Thereby, for example, proposed in Japanese Patent aid-Open Publication No. Sho 59(1984)-40964 is to provide a buckle disengagement device for automatically disengaging the buckle in order to let the passenger free. According to this structure, it is possible to disengage the buckle in emergency situations.
Nevertheless, if the buckle is disengaged due to a misdetection, the passenger must go through the trouble of reconnecting the tongue plate, which the webbing passes through, to the buckle.